Abstract: In accordance with the invention, there are electrocaloric devices, pyroelectric devices and methods of forming them. A device which can be a pyroelectric energy generator or an electrocaloric cooling device, can include a first reservoir at a first temperature and a second reservoir at a second temperature, wherein the second temperature is higher than the first temperature. The device can also include a plurality of liquid crystal thermal switches disposed between the first reservoir and the second reservoir and one or more active layers disposed between the first reservoir and the second reservoir, such that each of the one or more active layers is sandwiched between two liquid crystal thermal switches. The device can further include one or more power supplies to apply voltage to the plurality of liquid crystal thermal switches and the one or more the active layers.

Abstract: Provided are electrocaloric devices, pyroelectric devices and methods of forming them. A device which can be a pyroelectric energy generator or an electrocaloric cooling device, can include a first single-layer heat engine having a first side configured to be in contact with a first reservoir and a second side configured to be in contact with a second reservoir, wherein the first reservoir comprises a fluid. The device can also include a second single-layer heat engine having a first side in contact with the first reservoir and a second side in contact with a third reservoir and a channel disposed between the first single-layer heat engine and the second single-layer heat engine, the channel configured to transport the fluid from a first end to a second end. The device can further include one or more power supplies configured to apply voltages to the first and the second single-layer heat engine.

Abstract: In accordance with the invention, there are electrocaloric devices, pyroelectric devices and methods of forming them. A device which can be a pyroelectric energy generator or an electrocaloric cooling device, can include a first reservoir at a first temperature and a second reservoir at a second temperature, wherein the second temperature is higher than the first temperature. The device can also include a plurality of liquid crystal thermal switches disposed between the first reservoir and the second reservoir and one or more active layers disposed between the first reservoir and the second reservoir, such that each of the one or more active layers is sandwiched between two liquid crystal thermal switches. The device can further include one or more power supplies to apply voltage to the plurality of liquid crystal thermal switches and the one or more the active layers.

Abstract: In accordance with the invention, there are thermal switches, method of operating thermal switches and methods of forming thermal switches. A thermal switch can include a thin layer of liquid crystal disposed between a first surface of a first insulating substrate and a second surface of a second insulating substrate, wherein the liquid crystals are aligned at one or more of the first surface and the second surface due to surface preparation.

Abstract: Electromagnetic radiation detector elements and methods for detecting electromagnetic radiation, in particular, infrared radiation, are provided. The electromagnetic radiation detector element can include an electromagnetic radiation detector and a plasmonic antenna disposed over the electromagnetic radiation detector. The plasmonic antenna can include a metal film, a sub-wavelength aperture in the metal film, and a plurality of circular corrugations centered around the sub-wavelength aperture.

Abstract: Symmetric quantum dots are embedded in quantum wells. The symmetry is achieved by using slightly off-axis substrates and/or overpressure during the quantum dot growth. The quantum dot structure can be used in a variety of applications, including semiconductor lasers.

Abstract: A quantum dot active region is disclosed in which quantum dot layers are formed using a self-assembled growth technique. In one embodiment, growth parameters are selected to control the dot density and dot size distribution to achieve desired optical gain spectrum characteristics. In one embodiment, the distribution in dot size and the sequence of optical transition energy values associated with the quantum confined states of the dots are selected to facilitate forming a continuous optical gain spectrum over an extended wavelength range. In another embodiment, the optical gain is selected to increase the saturated ground state gain for wavelengths of 1260 nanometers and greater. In other embodiments, the quantum dots are used as the active region in laser devices, including tunable lasers and monolithic multi-wavelength laser arrays.

Abstract: Quantum dot active region structures are disclosed. In a preferred embodiment, the distribution in dot size and the sequence of optical transition energy values associated with the quantum confined states of the dots are selected to facilitate forming a continuous optical gain spectrum over an extended wavelength range. In one embodiment, the quantum dots are self-assembled quantum dots with a length-to-width ratio of at least three along the growth plane. In one embodiment, the quantum dots are formed in quantum wells for improved carrier confinement. In other embodiments, the quantum dots are used as the active region in laser devices, including tunable lasers and monolithic multi-wavelength laser arrays.

Abstract: A quantum dot active region is disclosed in which quantum dot layers are formed using a self-assembled growth technique. In one embodiment, growth parameters are selected to control the dot density and dot size distribution to achieve desired optical gain spectrum characteristics. In one embodiment, the distribution in dot size and the sequence of optical transition energy values associated with the quantum confined states of the dots are selected to facilitate forming a continuous optical gain spectrum over an extended wavelength range. In another embodiment, the optical gain is selected to increase the saturated ground state gain for wavelengths of 1260 nanometers and greater. In other embodiments, the quantum dots are used as the active region in laser devices, including tunable lasers and monolithic multi-wavelength laser arrays.

Abstract: Quantum dot active region structures are disclosed. In a preferred embodiment, the distribution in dot size and the sequence of optical transition energy values associated with the quantum confined states of the dots are selected to facilitate forming a continuous optical gain spectrum over an extended wavelength range. In one embodiment, the quantum dots are self-assembled quantum dots with a length-to-width ratio of at least three along the growth plane. In one embodiment, the quantum dots are formed in quantum wells for improved carrier confinement. In other embodiments, the quantum dots are used as the active region in laser devices, including tunable lasers and monolithic multi-wavelength laser arrays.